Why so angry?

I saw a bumper sticker on a car today promoting blasphemy day. The lizard decal and various other bumper stickers made it clear the owner did not believe in God. But it seemed to go further than that. I mean, blasphemy day, really?

I had another sort of encounter with an agnostic not too long ago. In a kind of confrontational manner, he suggested I shouldn’t go to a doctor since I believe in God. Huh?

I’m not shocked people don’t believe in God. I went through that phase myself, actually. It lasted only a couple of years. I couldn’t really keep it up when confronted with overwhelming evidence to the contrary. It doesn’t make me mad they don’t believe. I’m always kind of surprised and maybe a little sad for them but not angry.

What I do find so curious is when I meet (or drive behind) people that seem kind of pissed about it. What are they mad about exactly?